ScarHead

The only part I'm having trouble with is part C ... Help would be much appreciated.

*1________6.00 cm____________ *

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3.00cm | |

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*2 *3

For the figure shown above, (just in case it screws up the doodle, above is a [3cm X 6cm] rectangle with charges at the corners)

*1 = 8.0 microcoloumbs (uC) (top left corner)

*2 = 2 uC (bottom left corner)

*3 = 4 uC (bottom right corner)

A. Find the electric potential, taking zero at infinity, at hte upper right hand corner of the rectangle.

Found to be V = 2.67*10^6 V

B. Repeat, if the 2.0 uC charge is replaced with a charge of -2.0 uC.

Found this to be V = 2.13 *10^6 V

C. For the situations in both (a) and (b), how much work should be done to move a +6.0 uC charge from infinity to the upper right hand corner of the rectangle?

HELP!!!

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For each change listed below, state whether the magnitude of the charge on the upper plate of the capacitor increases, decreases, or remains the same.

i. Increase the distance between plates

ii. Increase the cross sectional area of the capacitor

iii. Increase the battery voltage

iv. Reverse the battery polarity

A hand pushes a 3 kg block along a table from point A to point C, as shown (see link). The table has been prepared so that the left half of the table from A to B is frictionless. The right half from B to C has a non-zero coefficient of friction equal to u. The hand pushes the block from A to C using a CONSTANT FORCE of 5 N. The block starts off at rest at point A and copes to a stop when it reaches point C. The distance from A to B is 0.5m and the distance from B to C is also 0.5m.

http://www.physics.umd.edu/perg/abp/TPProbs/Proble...

a. Describe in words the motion of the block as it moves from A to C.

b. What is the kinetic energy of the block at point B?

c. Draw a free-body diagram for the block when it is at point P. Make sure to properly label all forces in a way that indicates the type of force, the object that exerts the force, and the object the force is being exerted on.

d. What is the direction of the acceleration of the block at point P? If it is zero, say so explicitly. Explain your reasoning.

e. Does the magnitude of the acceleration increase, decrease, or remain the same as the block moves from B to C? Explain your reasoning.

f. What is the net work done on the object as it moves from A to B? From B to C?

g. Calculate the coefficient of friction between the block and the rough surface.

I really loathe friction when it comes to physics ... any help would be appreciated. Much thanks!

A student is in her dorm room, sitting on her bed doing physics homework. The door to her room is open. All of a sudden, she hears the voice of her ex-boyfriend down the hall, talking to the girl in the room next door. She wants to shut the door quickly, so she throws a bouncy ball (which she keeps next to the bed for this purpose) against the door. It hits the door squarely and bounces straight back. See image.

A. If the ball has a mass m, hits the door with a speed v, and bounces back with a speed essentially equal to v, what is the change in the ball's momentum?

B. if the ball was in contact with the door for a time (delta t), what was the average force exerted on the ball by the door?

C. Would she have been better off with a clay ball of the same mass that stuck to the door? Explain your reasoning.

D. Does the ball's effectiveness in closing the door depend on where on the door the ball hits? If it does, where should it hit to be the most effective? Explain your reasoning.

I am absolutely lost when it comes to elastic collisions ... any help would be awesome. Thanks in advance!!!

You are driving along the road in a rented moving van that has a mass of 4000 kg. you have slowed down to 7 m/s because you are in a school zone. It's a good thing you thought to do that because a group of first graders are just starting to cross the road. Just as you pass the children, you see a car of 1000 kg in the on coming lane heading straight for the children at 40 m/s. you have just enough time to swing into the oncoming lane and speed up a bit before making a head-on collision with the other car. Assuming the collision is inelastic, how fast do you need to go to stop the other car? Can you save the children?

I'm kind of torn between yes and no.

Two workers are carrying a 6 m ladder. The ladder has a mass of 15 kg. A cat, with a mass of 5 kg, jumps on the ladder and hangs on, 1 m from the edge of the ladder. How much force does each workman have to exert to hold the ladder up?

I'm kind of confused between reduction/oxidation and reducing agent/oxidizing agent. I know oxidation is losing electrons and pertains to the reducing agent, and that reduction is gaining electrons and pertains to the oxidizing agent. But I don't know which is which in equations ... any help would be great.

2 Fe(NO3)3 (aq) + H2S (aq) --> 2 FeS (s) + 6HNO3 (aq) + S (s)

Find substance oxidized, substance reduced, reducing agent, and oxidizing agent.

I know there's no such thing as negative frequency, my professor has said the same thing when I showed him the problem, but I don't get what I'm doing wrong ..... In the first part of the problem, I had to find the energy difference ---which came to be -8.37*10^-18 J.

For the next part, I'm supposed to find the wavelength and frequency ... I'm ending up with a frequency of -1.26*10^16. What am I doing wrong??? My professor's being no help and just says "You have the right idea, but frequency can't be negative". What does that mean?!?!?!?!?!?!

The first ionization energy (IE) of an atom can be measured by a technique known as photoelectron spectroscopy, in which light of wavelength is directed at an atom, causing an electron to be ejected from the atom. The kinetic energy of the ejected electron, E_k, is measured by determining the velocity of the electron and utilizing the relationship for the kinetic energy of a particle, E_k = 1/2 m v^2. Finally, the IE is determined by an application of the law of conservation of energy. The energy of the light directed at the atom must be equal to the sum of the energy needed to remove the electron from the atom, which is its ionization energy, and the kinetic energy of the ejected electron.

A photonelectron spectroscopy experiment is conducted in which light with wavelength = 58.4 nm is directed at a sample of rubidium, resulting in the ejection of electrons with a velocity of 2.45 *10^6 m/s. Use these experimental data to determine the IE of rubidium in kJ/mol.

I think I'm making this problem too complex for myself to understand ... isn't it basically saying that the IE is equal to the E_k? Is the answer 175 kJ?

Any help would be appreciated! Much thanks!

Arrange the following electron transitions in the hydrogen atom in order of increasing energy change without actually calculating all the energy changes:

a. n = 1 to n = 99

b. n = 3 to n = 80

c. n = 2 to n = 3

d. n = 1 to n = 3

e. n = 5 to n = 12

The Rydberg equation provided in the text is:

E = -R_h (1 / n^2) where R_h = 2.18 * 10^-18 J

I am not familiar with this version of the Rydberg equation ... I thought the Rydberg equation had the (1 / ni ^2 - 1/ nf ^2) part in it ..... so any help would be appreciated. Thanks in advance!

The first ionization energy (IE) of an atom can be measured by a technique known as photoelectron spectroscopy, in which light of wavelength is directed at an atom, causing an electron to be ejected from the atom. The kinetic energy of the ejected electron, E_k, is measured by determining the velocity of the electron and utilizing the relationship for the kinetic energy of a particle, E_k = 1/2 m v^2. Finally, the IE is determined by an application of the law of conservation of energy. The energy of the light directed at the atom must be equal to the sum of the energy needed to remove the electron from the atom, which is its ionization energy, and the kinetic energy of the ejected electron.

A photonelectron spectroscopy experiment is conducted in which light with wavelength = 58.4 nm is directed at a sample of rubidium, resulting in the ejection of electrons with a velocity of 2.45 *10^6 m/s. Use these experimental data to determine the IE of rubidium in kJ/mol.

I think I'm making this problem too complex for myself to understand ... isn't it basically saying that the IE is equal to the E_k? Is the answer 175 kJ?

Any help would be appreciated! Much thanks!

Small rockets have been used to probe the atmosphere for 40 years. Scientific packages in the nose cone of the rocket detect chemicals in the atmosphere and return to earth by parachute. One early such rocket, the Canadian Black Brant VI, was quite small ... about 9 feet ling with a mass of 100 kg, yet it could climb quite high. Be sure to explain your reasoning ...

A. When launched, the Black Brant VI could accelerate upward with a total acceleration of 5 g (with g - 9.8 g m/s^2) for 20 seconds. At the end of this acceleration phase, what was its velocity?

B. At the end of the acceleration phase, how high would it be?

C. At the end of the acceleration phase, the rocket turns off. How much longer will it continue to rise? Calculate the total height to which it will rise.

I really don't understand acceleration that well and always get confused between how position/velocity/acceleration work together ... Any help would be appreciated.

Consider two projectiles that can be shot upward by spring guns. Object A is made of solid aluminum and has a mass of 50 g. Object B is made of cast iron and has a mass of 200 g.

a. Mass A is shot straight up so that it exits the spring gun with a speed of 2/0 m/s. How high above the gun does it rise?

b. Masses A and B are both shot straight upward at the same time. Mass A is shot with a speed of 2 m/s and mass B with a speed of 1 m/s. Which one hits the ground first? Explain why.

c. In the situation in case (B), which ball goes higher? Explain why.

I can't seem to get part A ... Any help on that would be appreciated.

For B, would Mass B be the correct answer? Because it's heavier than Mass A?

For C, wouldn't the ball that goes higher be the first (Object A / Mass A) because it's lighter?

Any help will be appreciated! Thanks in advance!

Four different mice labeled A, B, C, and D ran the triangular maze. The picture that's shown on the paper is of an equilateral triangle. Mouse A went from the bottom left corner to the bottom right corner (directly) in t=2 seconds. Mouse B went from the lower left to the lower right and back to the lower left in t = 2 seconds. Mouse C went from the lower left corner to the topmost corner and back to the lower right corner (upside down V) in t = 4 seconds. Mouse D went from the lower left corner, to the top corner, to the lower right corner, and back to the lower left within t = 4 seconds.. They started in the lower left corner and followed the paths of the arrows.

Each description may refer to one or more mice ...

a. Which mouse had the largest average speed?

b. Which mouse had the largest total displacement?

c. Which mouse had an average velocity that points to the right?

d. Which mouse had the largest velocity?

My guess:

a. Mouse D had the largest average speed

b. I don't know this one!!!

c. Would Mice A and C both have an average velocity to the right?

d. I don't know this one!!!

If anyone can help me determine if my two guesses are right, I'd appreciate it. Also, please explain b. and d. because I don't understand them at all. Thanks in advance!

Vinegar is 5% acetic acid solution by mass. What is the molarity of vinegar? Assume density is 1g/mL. How many moles of 0.1 M NaOH are required to react completely with 1 L of the vinegar? How many L of NaOH is this?

I got the first part to be 0.833 M Vinegar ... it's the NaOH part I'm having trouble with. Any help would be appreciated! Thanks in advance!

Calculate the number of moles and grams of methanol that must be added to 2 moles of water to make a solution that has equal numbers of methanol and water molecules. How many total molecules does the resulting solution contain?

I'm kinda confused ... isn't methanol + water yielding methanol+water? I can't seem to figure out the chemical equation for this ... any help would be appreciated!

An environmental chemist collects a 0.4546 g sample of waste material from an industrial process that releases benzoic acid (HC7H5O2) plus additional inert compounds that are harmless to the environment. The solid sample is dissolved in 50 ml of water, in which it completely dissolves. The resulting solution required 10.10 ml of 0.1550 M NaOH for complete neutralization.

a. Write the titration reaction. Benzoic acid is monoprotic, releasing one hydrogen ion per molecule.

b. How many moles of NaOH were needed to titrate the sample?

c. How many moles of benzoic acid were present in the dissolved sample?

d. How many grams of benzoic acid were in the sample?

e. What is the mass percent of benzoic acid in the sample?

For the titration reaction equation, I'm not sure if this is right:

HC7H5O2 + NaOH --> NaC7H5O2 + H2O

And then from there, I don't understand what to do next ... the problem talks about a "waste sample", is that the NaC7...? I don't get it. Any help would be appreciated. Thanks in advance!

Assume that you have the following three solutions at your disposal: NaCl, Na2SO4, and NaOH. Your team's task is to make a flowchart showing the sequence of steps that you would use to separate the ions in each solution by precipitating each ion one at a time.

a. Solution A contains Ag+, Ba2+, and Fe3+.

b. Solution B contains Pb2+, Sr2+, and Ni2+

I don't really understand what this question is asking me to do and where to begin ... Any help would be appreciated. Thanks in advance!

Consider what would happen if 1 mole of pennies were distributed equally among the earth's population, which is currently estimated at 6*10^9.

a. How many pennies would each person get?

b. If you spend a mole of pennies at the rate of 1 million dollars per day, how many years will it take to spend all of the pennies? Use dimensional analysis to construct a clear, easy-to-follow solution.

c. Which has more monetary value, 15.00 moles of pennies or 0.800 moles of quarters?

d. The mass of one penny is 2.45g. What is the mass of 1 mole of pennies?

I really have difficulties with Avogadro's number ... if anyone can help with this, I'd appreciate it. Thanks in advance!